Compound molecular models

This photochemical/thermal isomerisation of the ruthenium-containing ring is accompanied by a dramatic geometrical change of the compound. Molecular modelling studies [92] suggest that the distance between the two... 

Schulten H.R., Interactions of dissolved organic matter with xenobiotic compounds Molecular modeling in water, Environ. Toxicol. Chem., 18, 1643, 1999. 

Among the bis-imidazole perylenes studied, XXa is the most sensitive compound. Molecular modeling studies indicate that XXa is the most planar molecule among XXa-d. Again, a closer intermolecular interaction is attained, which presumably leads to high photosensitivity [235]. 

The modeling of inorganic compounds in general is gaining more and more interest [25-28]. The authors of MOMEC addressed this in a monograph describing how molecular modeling techniques can be applied to metal complexes and how the results can be interpreted [29]. The current force field parameter set is available on the author s web site. 

P. Comba, T. W. Hambley, Molecular Modeling of Inorganic Compounds VCH, Wein-heim (1995). 

Compound Structural Formula Repulsive Electron Pairs of Electron Pairs Molecular Shape Molecular Model... 

Examine the molecular models of H2 HE CH4 CH3F and CF4 Find the calculated dipole moment of each compound and examine their electrostatic potential maps... 

The compound cyanoacetylene (HC=C—C=N) has been detected in interstellar space Make a molecular model or sketch the approximate geometry expected for this compound What IS the hybridization of nitrogen and each carbon" ... 

Write structural formulas or make molecular models for the most stable conformation of each of the following compounds... 

Compound A undergoes catalytic hydrogenation much faster than does compound B Why" Making molecular models will help... 

The strength of this bonding depends on the kind of ether Simple ethers form relatively weak complexes with metal ions but Charles J Pedersen of Du Pont discovered that cer tain polyethers form much more stable complexes with metal ions than do simple ethers Pedersen prepared a series of macrocyclic polyethers cyclic compounds contain mg four or more oxygens m a ring of 12 or more atoms He called these compounds crown ethers, because their molecular models resemble crowns Systematic nomencla ture of crown ethers is somewhat cumbersome and so Pedersen devised a shorthand description whereby the word crown is preceded by the total number of atoms m the ring and is followed by the number of oxygen atoms... 

The compound shown is diethylstilbestrol (DES) it has a number of therapeutic uses in estrogen replacement therapy DES is not a steroid but can adopt a shape that allows it to mimic estrogens such as estradiol (p 1100) and bind to the same receptor sites Construct molecular models of DES and estradiol that illustrate this similanty in molecular size shape and location of polar groups... 

Another group of macrocyclic ligands that have been extensively studied are the cycHc polyethers, such as dibenzo-[18]-crown-6 (5), in which the donor atoms are ether oxygen functions separated by two or three carbon atoms. The name crown ethers has been proposed (2) for this class of compounds because of the resemblance of their molecular models to a crown. Sandwich stmctures are also known in which the metal atom is coordinated with the oxygen atoms of two crown molecules. 

Three-Dimensional Modeling of Chemical Structures. The two-dimensional representations of chemical stmctures are necessary to depict chemical species, but have limited utiHty in providing tme understanding of the effects of the three-dimensional molecule on properties and reactive behavior. To better describe chemical behavior, molecular modeling tools that reflect the spatial nature of a given compound are required. 

Ethynylation of 3j -hydroxy-16a-methyl-5a-androstan-17-one in a mixture of diethylene glycol dimethyl ether and diethylene glycol monoethyl ether in the presence of potassium hydroxide produces two isomeric 17-ethynyl derivatives. This result is not unexpected since molecular models suggest that the steric influence of the 13/ -methyl group is nearly offset by the 16a-methyl group. The presence of a 16a-acetoxy group in the estrone series also leads to the formation of epimeric 17-ethynyl compounds (61) and (62) on reaction with acetylenedimagnesium bromide. 

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